Sep 20, 2026Silicone Guides
5 Checks That Reduce Rework in Custom Silicone Projects
Five pre-tooling checks that help reduce rework in custom silicone projects: drawing, materials, assembly, molding risks and approval criteria.
Most rework starts earlier than people think. Sometimes before the first sample. Often before the mold.
The objective is not to eliminate every possible project change. That is unrealistic. The objective is to move as many changes as possible to the stage where they are still inexpensive.
1. Review the Drawing
Look for thin sections, difficult geometry, deep undercuts, sharp transitions, insufficient draft and hard-to-fill areas.
A feature that looks small in CAD can become the reason for repeated sampling later.
2. Review the Materials
Silicone, plastic and metal behave differently during molding and after assembly. Before tooling, confirm substrate material, silicone type, hardness requirement, bonding method, process-temperature compatibility and environmental requirement.
3. Review the Assembly
A molded component should not be evaluated only as a separate part. Check fit, alignment, tolerance stack-up, compression, interface and final user function.
A part can pass dimensional inspection and still create an assembly problem.
4. Review the Molding Risks
Before tooling, identify venting, material flow, insert positioning, demolding, critical cosmetic surfaces and likely defect areas.
These risks should influence tooling design instead of being discovered only during trial molding.
5. Define What "Approved" Means
A project becomes difficult when the sample is approved without a clear standard. Define the approval points:
· dimensions
· appearance
· color
· tactile feel
· bonding
· assembly
· functional checks
The approved sample and agreed criteria should become the production reference.
Why This Reduces Rework
The cost of a change generally rises as the project moves forward: CAD → Tooling → Sample → Production → Shipment.
A geometry change in CAD may take minutes. The same geometry change after tooling can mean mold modification, a new sample, a new approval and schedule delay.
The cheapest engineering change is usually the one made before the mold is cut.
Related Pages & Case Studies
· OEM & ODM Product Development - /product-development
· Custom Molded Silicone - /custom-silicone-molding
· Case study: Making Bulk Production Match the Approved Sample - /case-study-sample-to-bulk-silicone-consistency
· Case study: Avoiding Tooling Rework With a Pre-Mold DFM Review - /case-study-lsr-overmolding-dfm-before-tooling
Want a Second Review Before Tooling?
Send us the STEP file, material information and assembly requirement. We can review the design for common silicone and overmolding risks before production starts.
Request a Pre-Tooling Review - /contact-us#project-inquiry
